Definition of stroma in English:


Pronunciation /ˈstrōmə/ /ˈstroʊmə/


  • 1Anatomy Biology
    The supportive tissue of an epithelial organ, tumor, gonad, etc., consisting of connective tissues and blood vessels.

    ‘a loose stroma of connective tissue’
    • ‘the virus caused necrosis of epithelium and stroma’
    • ‘Loose connective tissue stroma predominated in the less cellular areas.’
    • ‘The stroma consists of fatty tissue and ligaments surrounding the ducts and lobules, blood vessels and lymphatic vessels.’
    • ‘The deeper regions of the tumor showed hypocellularity and had an abundance of loose edematous stroma.’
    • ‘Tumor cells were embedded in a loose collagenous stroma.’
    • ‘The bland fibrous stroma is infiltrated by mature lymphocytes and plasma cells.’
    1. 1.1The spongy framework of protein fibers in a red blood cell or platelet.
      ‘The endometrial stroma has a framework consisting of reticular fibers and stromal cells.’
      • ‘The surrounding stroma was infiltrated by plasma cells and scattered aggregates of lymphocytes, forming follicles with germinal centres.’
      • ‘Typical plaques showed proliferation of myofibroblastic cells with myxoid stroma.’
      • ‘There is no cellular or architectural atypia of the lobules or stroma.’
      • ‘The results indicate that the stroma contains some rather fragile enzymes.’
    2. 1.2Botany The matrix of a chloroplast, in which the grana are embedded.
      ‘Chloroplast envelopes, stacked grana and unstacked stroma thylakoids were well-defined.’
      • ‘There is characteristically a dense sparsely cellular fibrous stroma.’
      • ‘Granules of different sizes were noted in the chloroplast stroma in all treatments.’
      • ‘The relative amount of stroma thylakoids is also increased, while the portion of grana thylakoids is lowered.’
      • ‘Thylakoids of grana stacks are mostly abundant in PSII complexes, while PSI complexes are predominant in stroma lamellae.’
  • 2Botany
    A mass of fungal tissue that has spore-bearing structures either embedded in it or on its surface.

    ‘the fruiting body is tightly compressed and sessile on a stroma’
    • ‘This latter consisted of a few membranes irregularly distributed in the stroma or tightly pressed to form very electron-dense stacks.’
    • ‘During in vivo measurements, excitation light is incident upon the epithelium, and must travel through this tissue layer before reaching the stroma.’
    • ‘Transport proteins in the inner plastid envelope membrane connect the metabolism of plastid stroma and surrounding cytoplasm.’
    • ‘Very few dots are localized in the stroma of the amyloplasts.’
    • ‘A few times, dots are observed in the stroma of the amyloplasts.’


Mid 19th century modern Latin, via late Latin from Greek strōma ‘coverlet’.